We have recently applied the non-destructive technique of three-dimensional magnetic resonance imaging (MRI) microscopy to human cancellous bone biopsies (transcortical iliac crest) to generate holographic representations of trabecular structure. We have developed software to provide quantitative descriptions of trabecular architecture in terms of topology and geometry. In terms of validation, we tested: 1) the reproducibility of connectivity density measurements from repeated, independent MRI microscopy of biopsy mineral skeletons; 2) the relationship between connectivity density and sample examination volume; 3) the heterogeneity within biopsy specimens; and 4) the influence of microscopic resolution. In particular, we have investigated connectivity, nodal density, and bone volume fraction for a group of 10 biopsies, as are described in our manuscript "Connectivity in human cancellous bone by 3D MRI Microscopy", Medical Physics 24: 1409-1420, 1997. (Service 12) REPORT PERIOD: (09/01/97-08/31/98)